Starship Fourth Flight Test Brings Key Achievements

Yesterday, SpaceX carried out the fourth test flight of its future heavy rocket Starship, which will take humans back to the Moon with the Artemis program and subsequently to Mars, with the goal of making us a multiplanetary species. As is well known, SpaceX has always developed its vehicles and technologies through an iterative design methodology, uncommon for this sector.

The numerous test flights of Starship are also part of this development process that has enabled Elon Musk’s company to create a vehicle like the Falcon 9, which has radically changed the future of space exploration. The continuous tests lead to developments and improvements that progressively perfect the design.

The fourth flight of Starship confirmed the success of this approach, with many key achievements essential for the continuation of the program.

The launch

On June 6, at 12:50 UTC, Booster 11, with Ship 29 on top, cleared the launch pad at Starbase, Texas. Unlike the previous two launches, not all Raptor engines functioned correctly during the ascent phase. One of the 33 engines shut down shortly after liftoff. However, the ascent burn continued seamlessly. In fact, Starship is designed to fly safely even without one or more engines running.

Nearly three minutes into the flight Starship successfully carried out for the third time the hot-stage separation. This time, all 13 central engines on Super Heavy re-ignited, successfully completing the boostback burn, which directed the booster toward the planned landing zone. A few seconds later the hot staging ring separated from the first stage, a temporary new maneuver to reduce weight.

The booster then continued its descent without issues until 1 km altitude. Unlike the third flight, 12 Raptors successfully ignited, simulating a nominal landing. Super Heavy then settled on the sea’s surface, providing us with incredible images before tipping over to one side.

The first stage flight achieved all the objectives set by SpaceX. Soon, we might witness the first landing on the pad with capture by the tower.

Ship 29: from liftoff to splashdown

After separation, Ship 29 ignited all six of its engines for several minutes until reaching a speed close to that of orbital insertion. After shutdown, Starship continued nominally its 40-minute coast phase. Right from the start, the great stability the vehicle maintained until entry into the atmosphere was visible.

Nearly 50 minutes after liftoff, Starship began its atmospheric reentry over the Indian Ocean. The most anticipated moment of the mission.

For many minutes, the spacecraft continued its reentry smoothly, once again providing us with footage never seen before, with the hot plasma illuminating the heat shield.

Unfortunately, at an altitude of approximately 60 kilometers, plasma began to penetrate between the ceramic thermal protection tiles of one of the aerodynamic control flaps. As the descent progressed, a significant portion of the protective heat shield started to detach, exposing the stainless steel structure to extreme temperatures exceeding 1000 degrees Celsius. Some of the metal melted, causing damage to the wing. However, exceeding expectations, it managed to endure beyond the period of maximum heat and maintained control of the spacecraft.

Starship made a controlled reentry, successfully making it through the phases of peak heating and max aerodynamic pressure and demonstrating the ability to control the vehicle using its flaps while descending through the atmosphere at hypersonic speeds pic.twitter.com/p8bC9UweLx

— SpaceX (@SpaceX) June 6, 2024

Starship thus managed to reach the ocean, more or less intact, and also complete the landing maneuver in a vertical position with the ignition of three engines. In the last moments captured by the camera, it is possible to see the spacecraft settling in the water.

Significant progress toward next launch

Awaiting further feedback from SpaceX on some of the main issues encountered, such as the shutdown of some Raptors and the behavior of the tiles, we can say that this flight test was overall a great success. All primary mission objectives were achieved, and some crucial aspects for the vehicle’s reusability behaved as planned. Many of the issues encountered in past launches have been resolved.

Now, thanks to some changes made by the Federal Aviation Administration (FAA) in the last launch license issued to SpaceX, there could be a reduction in the timeframe towards the next Starship launch.